The continual demand for enhanced integrated circuit performance has resulted in, among other things, a dramatic reduction of semiconductor device geometries, and continual efforts to optimize the performance of every substructure within any semiconductor device. A number of improvements and innovations in fabrication processes, material composition, and layout of the active circuit levels of a semiconductor device have resulted in very high-density circuit designs. Increasingly dense circuit design has not only improved a number of performance characteristics, it has also increased the importance of, and attention to, semiconductor material properties and behaviors.
The increased packing density of the integrated circuit generates numerous challenges to the semiconductor manufacturing process. Nearly every device must be smaller without degrading operational performance of the integrated circuitry. High packing density, low heat generation, and low power consumption, with good reliability must be maintained without any functional degradation. Increased packing density of integrated circuits is usually accompanied by smaller feature size.
As device geometries and features continually decrease in size, and as new materials are introduced into semiconductor fabrication processes, many traditional semiconductor fabrication techniques and processes are rendered impractical or unusable. In order to adapt to the unique demands of new technologies (e.g., deep sub-micron), existing fabrication processes must renovated, or abandoned in favor of new fabrication processes. Consider, for example, conventional semiconductor deposition processes. Some conventional deposition techniques are simply not capable of depositing semiconductor material at sub-micron levels or tolerances. Alternative deposition processes—such as thin-film deposition—have been developed in response, to more adequately accommodate the demands of fabricating sub-micron device structures.
Thin-film deposition techniques, and other similar processes, often rely on relatively large, flat dispensing apparatus—commonly referred to as “showerheads”—to deposit a very fine layer of a semiconductor material across a significant portion of a semiconductor wafer surface. Ideally, if the showerheads are properly aligned, the semiconductor material is deposited in a uniform manner across the surface. This is important because non-uniformities in thin-film materials can cause a number of variances in device performance or reliability, degrading process yields. In many cases, however, showerheads frequently fall out of alignment during processing. Deposition on semiconductor wafers must therefore routinely be halted, while adjustments are made to properly align the showerheads.
This routine process interruption introduces a significant degree of delay and inefficiency into fabrication processes utilizing such apparatus. Such inefficiencies and delays are further compounded and increased by a number of impediments inherent in conventional showerhead alignment methodologies. Most such systems require numerous iterations (e.g. 6, 8, 12) of laborious and tedious manual measurements and calibrations—each of which may take several hours, individually.
These manual adjustment procedures thus frequently take many (e.g., ˜12 or more) hours and, in some cases, days to complete—as the deposition system is repetitively operated, measured and adjusted until proper alignment is achieved. This causes a number of bottlenecks in the fabrication process, and places an inordinate drain on other process resources. Furthermore, conventional alignment methodologies commonly rely, in large part, on the subjective measurements and adjustments of operators performing the alignment procedures. This introduces, to at least a minimal extent, some degree of human error and unavoidable incongruity to the thin film deposition process. Non-uniformities that result over time can have further detrimental impacts on process yields and stability.
As a result, there is a need for a system for aligning deposition equipment and apparatus, such as thin-film deposition showerheads, that provides accurate and consistent equipment alignment while reducing or eliminating the need for iterative alignment processes, improving process efficiency, yield and reliability in an easy, efficient and cost-effective manner.